1. Field of the Invention
The invention relates to an extract from the leaves of Toona sinensis Roem., a process of preparing the extract, and uses of the extract in the treatment of ovarian and/or bladder cancer.
2. Description of the Related Art
Toona sinensis Roem. or Cedrela sinensis, commonly known as Chinese mahogany cedar or Chinese Toona, is a perennial deciduous tree of the family Meliaceae. Its bark is reddish brown. Its tender leaves are edible and are available for picking almost all year around. Originally grown in the south-eastern part, the south-western part and the northern part of China, Toona sinensis is now being planted in many countries. (Jennifer M. Edmonds and Martin Staniforth, TOONA SINENSIS (Meliaceae), Curtis's Botanical magazine, 15 (3), 186–193, 1998; Xiao-Dong Luo et al., Fitoterapia, 71, 492–496, 2000; Jong-Cheol Park et al., Kor. J. Pharmacogn, 27(3), 219–223, 1996).
Because the entire tree of Toona sinensis is useful, it has high economic value. According to reports, almost every part of Toona sinensis, including seeds, bark, root bark, petioles, and leaves, has a medicinal effect (Jennifer M. Edmonds and Martin Staniforth, 1998, supra; Jong-Cheol Park et al., 1996, supra).
Seeds of Toona sinensis contain oil, which is colorless and fragrant and can be used as edible oil. Shoots and leaves of Toona sinensis are rich in carotene, amino acids and vitamins, and are therefore quite popular as a vegetable. In addition, mellowed leaves can be used as animal fodder.
According to literatures (Jennifer M. Edmonds and Martin Staniforth, 1998 supra; Xiao-Dong Luo et al., 2000, supra) the bark, root bark and seeds of Toona sinensis are useful in the treatment of neuralgia, duodenal ulcer, stomach upsets, gonorrhea, menstrual disorder, ascariasis, rheumatoid arthritis, and cancer, and are useful as an astringent, a carminative, an analgesic, and in suppressing growth of typhoid bacillus and amoeba protozoa (Si-Ming Yu and Ze-Dang Zhang, Journal of Anhui University Natural Science Edition No. 4, 91–94, 1990; Yue-Zhen Liu and Yu-Ping Li, Hebei Forestry Technology, No. 4, 51–52, Dec. 1997).
According to literatures, leaves of Toona sinensis have anti-inflammatory, antidoting and worm-killing effects, and are useful for treating enteritis, dysentery, carbuncles, boils, dermatitis rhus, scabies, and tinea blanca, as well as for improving body health. In addition, aqueous extracts of leaves of Toona sinensis have been used as a folk medicine for improving hypertension and diabetes. Hseng-Kuang Hsu et al. found that aqueous extracts of Toona sinensis leaves are capable of lowering blood sugar in alloxan-induced diabetic rats (Wang PH et al., Toona sinensis increase GLUT4 glucose transporter protein in adipose tissue from Alloxan-induced diabetic rats, Annual Conference of Biomedical Science, p. 198, 2001). In another study, it was found that aqueous extracts from leaves of Toona sinensis are capable of suppressing proliferation of human lung adenocarcinoma cells A549 (Hui-Chiu Chang et al. (2002), American Journal of Chinese Medicine, Vol. 30, Nos. 2 & 3, 307–314).
In the other aspects, leaves of Toona sinensis are used as a dyeing agent or glaze.
In addition, as the wood of Toona sinensis is hardy, delicate, and resistant to warping, cracking and moisture, it is often used as timber for high-grade furniture, shipbuilding, bridge construction, etc. It is also used in the making of bats for table-tennis, rackets for badminton and tennis, and musical instruments.
Toona sinensis is also a good species for forestation to prevent landslides. In addition, Toona sinensis oil can be extracted from the wood of Toona sinensis to be used as an aroma enhancer for cigars.
To the inventors' knowledge, no literature or prior patent application has taught or suggested that the leaves of Toona sinensis or extracts from the leaves of Toona sinensis have activity in suppressing growth of ovarian cancer cells, and are therefore useful in the preparation of medicaments for the treatment of ovarian cancer.